Crimidine (2‐chloro‐4‐(dimethylamino)‐6‐methylpyrimidine) poisoning in a dog due to ingestion of the rodenticide Castrix®

The diagnosis and treatment of a case of crimidine poisoning in a dog are described. Presenting signs were seizures and vomiting. The vomitus contained a purple coloured cereal grain. The signs and grain colour were suggestive for a rodenticide with convulsive effects The diagnosis of crimidine poisoning was made by thin layer chromatography and was later confirmed by finding the source of the poison. Except for the administration of Vit B6, the specific antidote for crimidine, general treatment principles for poisoning were followed. The treatment of crimidine poisoning is time consuming and requires intensive care facilities.     

Polypeptide Modulators of TRPV1 Produce Analgesia without Hyperthermia

Transient receptor potential vanilloid 1 receptors (TRPV1) play a significant physiological role. The study of novel TRPV1 agonists and antagonists is essential. Here, we report on the characterization of polypeptide antagonists of TRPV1 based on in vitro and in vivo experiments. We evaluated the ability of APHC1 and APHC3 to inhibit TRPV1 using the whole-cell patch clamp approach and single cell Ca²⁺ imaging. In vivo tests were performed to assess the biological effects of APHC1 and APHC3 on temperature sensation, inflammation and core body temperature. In the electrophysiological study, both polypeptides partially blocked the capsaicin-induced response of TRPV1, but only APHC3 inhibited acid-induced (pH 5.5) activation of the receptor. APHC1 and APHC3 showed significant antinociceptive and analgesic activity in vivo at reasonable doses (0.01–0.1 mg/kg) and did not cause hyperthermia. Intravenous administration of these polypeptides prolonged hot-plate latency, blocked capsaicin- and formalin-induced behavior, reversed CFA-induced hyperalgesia and produced hypothermia. Notably, APHC3’s ability to inhibit the low pH-induced activation of TRPV1 resulted in a reduced behavioural response in the acetic acid-induced writhing test, whereas APHC1 was much less effective. The polypeptides APHC1 and APHC3 could be referred to as a new class of TRPV1 modulators that produce a significant analgesic effect without hyperthermia.     

Marine Derived Hamacanthins as Lead for the Development of Novel PDGFRβ Protein Kinase Inhibitors

In this study, we report on pyrazin-2(1H)-ones as lead for the development of potent adenosine triphosphate (ATP) competitive protein kinase inhibitors with implications as anti-cancer drugs. Initially, we identified the pyrazin-2(1H)-one scaffold from hamacanthins (deep sea marine sponge alkaloids) by Molecular Modeling studies as core binding motif in the ATP pocket of receptor tyrosine kinases (RTK), which are validated drug targets for the treatment of various neoplastic diseases. Structure-based design studies on a human RTK member PDGFR (platelet-derived growth factor receptor) suggested a straight forward lead optimization strategy. Accordingly, we focused on a Medicinal Chemistry project to develop pyrazin-2(1H)-ones as optimized PDGFR binders. In order to reveal Structure-Activity-Relationships (SAR), we established a flexible synthetic route via microwave mediated ring closure to asymmetric 3,5-substituted pyrazin-2(1H)-ones and produced a set of novel compounds. Herein, we identified highly potent PDGFR binders with IC₅₀ values in an enzymatic assay below µM range, and possessing significant activity against PDGFR dependent cancer cells. Thus, marine hamacanthin-derived pyrazin-2(1H)-ones showing interesting properties as lead for their further development towards potent PDGFR-inhibitors.     

Effect of maropitant,a neurokinin‐1 receptor antagonist,on the minimum alveolar concentration of sevoflurane during stimulation of the ovarian ligament in cats

ObjectiveDetermine if maropitant decreases the minimum alveolar concentration (MAC) of sevoflurane during stimulation of the ovarian ligament in cats.Study designProspective study.AnimalsFifteen, female cats weighing 2.5 ± 0.6kg (mean ± SD).MethodsAnesthesia was induced and maintained with sevoflurane. The right ovary was accessed via laparoscopy. A suture around the ovary and ovarian ligament was exteriorized through the abdominal wall for stimulation. A stimulus–response curve was created to identify the optimal force for MAC comparisons. In 10 cats, MAC was determined with only sevoflurane (baseline) then after 1 and 5 mg kg^?1 intravenous maropitant administration. The stimulation tension force used was 4.9 N. Repeated measures anova was used to compare the groups. MAC was defined as the average of the cross‐over concentrations and reported MAC is adjusted to sea‐level and depicted as mean ± SD.ResultsThe stimulus‐response curve was hyperbolic and plateaued at 4.3 ± 3 N. The optimal tension force chosen to compare MAC was 4.9 N. The baseline sevoflurane MAC was 2.96 ± 0.3%. Maropitant, 1 mg kg^?1, decreased the MAC to 2.51 ± 0.3% (15%, p < 0.01). The higher maropitant dose of 5 mg kg^?1 did not change MAC further when compared to the low dose (2.46 ± 0.4%, p = 0.33).Conclusion and clinical relevanceThe ovarian ligament stimulation model is suitable to determine MAC during visceral stimulation in cats. Maropitant decreased the anesthetic requirements during visceral ovarian and ovarian ligament stimulation in cats. Maropitant (1 mg kg^?1) decreases MAC by 15%; a higher dose had no additional effect.     

TRPM2 channel is essential for ammonia intoxication in astrocytes

AIM: To study the effects of transient receptor potential melastatin 2 (TRPM2) cation channel on ammonia intoxication in astrocytes.METHODS: Primary astrocytes were isolated, cultured and divided into 5 groups: control group, ammonium chloride (NH4Cl) treatment group, NH4Cl+3-aminobenzamide (3-AB) treatment group, NH4Cl+PJ-34 treatment group, and TRPM2 knockout+NH4Cl treatment group. Cell viability, caspase-3 activity, cell necrosis and cell volume were measured to assess the extent of ammonia toxicity. Whole-cell patch-clamp was performed to record the currents via TRPM2 channels.RESULTS: NH4Cl caused cell swelling accompanied with cell necrosis. The poly(ADP-ribose) polymerase (PARP) inhibitors, 3-AB and PJ-34, inhibited the cation currents activated by NH4Cl, and attenuated NH4Cl-induced cell damage. In TRPM2-deficient astrocytes, decreased cell damage was observed.CONCLUSION: TRPM2 activation is essential for cell swelling and necrosis in astrocytes exposed to NH4Cl. NH4Cl-triggered astrocyte swelling is closely correlated with necrosis.     

Effects of mesenchymal stem cells,fusion protein of tumor necrosis factor receptor Ⅱ-IgG Fc and mesalazine on disease activity index and tissue damage index of TNBS-induced colitis in rats

AIM: To study the effects of mesenchymal stem cells (MSCs), the fusion protein of tumor necrosis factor receptorⅡ-IgG Fc (TNFRⅡ-IgG) and mesalazine on the disease activity index (DAI) and tissue damage index (TDI) in the rat model of colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). METHODS: MSCs were cultured in low-glucose DMEM containing 10% FBS. Eighty-one Sprague-Dawley rats were used in the study and the model of colitis induced by TNBS/ethanol was established. The rats were randomly divided into 6 groups: normal control group (A), colitis group (B), MSCs treatment 1 (3×106 MSCs) group (C), MSCs treatment 2 (5×106 MSCs) group (D), TNFRⅡ-IgG treatment group (E) and mesalazine treatment group (F). The scores of DAI were used to record the manifestations of the rats, colon macroscopic damage index (CMDI) was used to describe the macroscopic features of the colon, and the scores of TDI were estimated by determining the pathological changes of the colon under microscope. RESULTS: Pure MSCs were gained by 3 times of passages. Compared with group A, the scores of DAI, CMDI and TDI in group B were always significantly increased. On day 6, these scores in every group except group A were not different obviously. On day 9, the scores in group C,group D and group F were lower than those in group B, and no statistic difference between group C and group D was observed. On day 14, the scores in group C, group D, group E and group F were lower than those in group B, and the scores in the groups were group F > group E > group C > group D. CONCLUSION: MSCs, TNFRⅡ-IgG and mesalazine used for 14 d significantly improve the scores of DAI, CMDI and TDI in the rats with colitis induced by TNBS. The method using MSCs is better than those using TNFRⅡ-IgG and mesalazine.     

低密度脂蛋白受体基因研究进展

低密度脂蛋白受体(LDLR)是一种细胞表面糖蛋白,广泛存在于体内许多组织细胞中,对脂蛋白代谢发挥重要作用。本文主要对LDLR生物学功能与基因结构,基因多态性与血脂相关性LDLR表达与疾病相关性进展作以综述。     

鹅催乳素受体基因克隆与表达

应用RACE-PCR技术,克隆了全长3 159 bp鹅催乳素受体基因(gPRLR)cDNA.序列分析表明, cDNA含443 bp 5′-UTR、2 496 bp编码区(含终止密码子TAA)和220 bp 3′-UTR.比对鸡催乳素受体基因并将前330 bp看作第1外显子,则gPRLR基因可划分为14个外显子.推导的蛋白序列含831个氨基酸,与鸡、鸽及火鸡PRLR的同源性分别为87.7%、85.2%和84.8%,其N末端含24个氨基酸的信号肽,成熟蛋白含807个氨基酸.gPRLR mRNA在成年鹅睾丸、输精管、卵巢、输卵管、肾、大肠、小肠、脾组织中均有表达,其中以肾、睾丸、大肠及小肠中表达最为丰富.     

脱落酸受体调控剂分子设计的研究进展

非生物胁迫会严重影响植物的生长发育,危害农业生产。脱落酸(abscisic acid,ABA)可以调控植物生长发育和提高植物的胁迫抗逆能力,能够有效缓解这一问题。但ABA存在代谢的不稳定性、易反式异构化等缺陷制约其应用。而ABA受体调控剂具有与ABA类似的生理调控功能,因此研究和开发ABA受体调控剂具有重要的意义。近些年研究者们相继设计了多个ABA受体调控剂,而关于ABA受体调控剂分子设计的全面总结鲜少报道。该文首先对ABA受体蛋白的发现及信号传导机制进行讨论,同时对现有的ABA受体调控剂的分子设计方法进行综述并介绍了其对调控植物表型的影响,最后讨论了ABA受体调控剂目前存在的问题,以期为进一步探索ABA受体调控剂的生物合理设计提供借鉴和参考。     

经注射接种的LPS在异育银鲫体内的分布

从柱状嗜纤维菌(Cytophaga columnaris)中提取脂多糖(LPS)，并制备荧光标记的大白鼠抗LPS抗体。经异育银鲫的胸鳍基部注射LPS后，应用免疫荧光抗体技术，观察了LPS在受免鱼的肾、脾、肝和鳃等组织中的动态分布。结果表明，注射接种LPSlh后，试验鱼的肾、脾和肝脏组织切片中即有荧光出现，3h后在试验鱼的鳃组织切片中也有荧光出现。说明接种的LPS在1h内就已经进入试验鱼的肾、脾和肝脏，而在3h内LPS进入了鳃组织。接种LPS48h后，LPS在试验鱼的脾、肝和鳃组织中消失，组织切片中已经观察不到荧光现象，而在肾组织中尚有LPS存在。